And so they returned to their outpost like good soldiers and sat outside on the little veranda as night began to fall. And they stared despondently at the white light and listened to the faint sound of music. And they waited for the legend to emerge from his cave. At six o’clock, having seen no evidence of him since the previous evening, they reached the conclusion that they had been duped. They didn’t dare enter his studio to confirm their suspicions. Instead, they spent several minutes quarreling over who should break the news to Uzi Navot. In the end, it was Lior, the older and more experienced of the two, who placed the call. He was a good boy with a bright future. He had just drawn the wrong assignment at the wrong time.

THERE WERE far worse places for a grounded defector to spend his final days than Bristol Mews. It was reached by a passageway off Bristol Gardens, flanked on one side by a Pilates exercise studio that promised to strengthen and empower its clients and on the other by a disconsolate little restaurant called D Place. Its courtyard was long and rectangular, paved with gray cobblestone and trimmed in red brick. The spire of St. Saviour Church peered into it from the north, the windows of a large terrace house from the east. The door of the tidy little cottage at No. 8, like its neighbor at No. 7, was painted a cheerful shade of bright yellow. The shades were drawn in the ground-floor window. Even so, Gabriel could see a light burning from within.

He had arrived in London in midafternoon, having flown to the British capital directly from Rome using a false Italian passport and a ticket purchased for him by a friend at the Vatican. After performing a routine check for surveillance, he had entered a phone box near Oxford Circus and dialed from memory a number that rang inside Thames House, headquarters of MI5. As instructed, he had called back thirty minutes later and had been given an address, No. 8 Bristol Mews, along with a time: 7 p.m. It was now approaching 7:30. His tardiness was intentional. Gabriel Allon never arrived anywhere at the time he was expected.

Gabriel reached for the bell, but before he could press it, the door retreated. Standing in the entrance hall was Graham Seymour, MI5’s deputy director. He wore a perfectly fitted suit of charcoal gray and a burgundy necktie. His face was fine boned and even featured, and his hair had a rich silvery cast to it that made him look like a male model one sees in ads for costly but needless trinkets-the sort who wears expensive wristwatches, writes with expensive fountain pens, and spends his summers sailing the Greek islands aboard a custom-made yacht filled with younger women. Everything about Seymour spoke of confidence and composure. Even his handshake was a weapon designed to demonstrate to its recipient that he had met his match. It said Seymour had gone to the better schools, belonged to the better clubs, and was still a force to be reckoned with on the tennis court. It said he was not to be taken lightly. And it had the added benefit of being true. All but the tennis. In recent years, a back injury had diminished his skills. Though still quite good, Seymour had decided he was not good enough and had retired his racquet. Besides, the demands of his job were such that he had little time for recreation. Graham Seymour had the unenviable task of keeping the United Kingdom safe in a dangerous world. It was not a job Gabriel would want. The sun may have set on the British Empire long ago, but the world’s revolutionaries, exiles, and outcasts still seemed to find their way to London.

“You’re late,” Seymour said.

“The traffic was miserable.”

“You don’t say.”

Seymour snapped the dead bolt into place and led Gabriel into the kitchen. Small but recently renovated, it had sparkling German appliances and Italian marble counters. Gabriel had seen many like it in the home-design magazines Chiara was always reading. “Lovely,” he said, looking around theatrically. “Makes one wonder why Grigori would want to leave all this to go back to dreary Moscow.”

Gabriel opened the refrigerator and looked inside. The contents left little doubt that the owner was a man of middle age who did not entertain often, especially not women. On one shelf was a tin of salted herring and an open jar of tomato sauce; on another, a lump of pâté and a wedge of very ripe Camembert cheese. The freezer contained only vodka. Gabriel closed the door and looked at Seymour, who was peering into the filter basket of the coffeemaker, his nose wrinkled in disgust. “I suppose we really should get someone in here to clean up.” He emptied the coffee filter into the rubbish bin and gestured toward the small café-style table. “I’d like to show you something. It should put to rest any questions you have about Grigori and his allegiances.”

The table was empty except for an attaché case with combination locks. Seymour manipulated the tumblers with his thumbs and simultaneously popped the latches. From inside he removed two items: a portable DVD player of Japanese manufacture and a single disk in a clear plastic case. He powered on the device and loaded the disk into the drawer. Fifteen seconds later, an image appeared on the screen: Grigori Bulganov, sheltering from a gentle rain at the entranceway of Bristol Mews.

In the bottom left of the image was the location of the CCTV camera that had captured the image: BRISTOL GARDENS. In the top right was the date, the tenth of January, and beneath the date was the time: 17:47:39 and counting. Grigori was now lighting a cigarette, cupping the flame in his left hand. Returning the lighter to his pocket, he scanned the street in both directions. Apparently satisfied there was no danger, he dropped the cigarette to the ground and started walking.

WITH THE cameras tracking his every move, he made his way to the end of Formosa Street and crossed the Grand Union Canal over a metal footbridge lined with spherical white lamps. Four youths in hooded sweatshirts were loitering in the darkness on the opposite bank; he slipped past them without a glance and walked past the colony of dour council flats lining Delamere Terrace. It was a few seconds after six when he descended a flight of stone steps to the boat basin known as Browning’s Pool. There, he entered the Waterside Café, emerging precisely two minutes and fifteen seconds later, holding a paper cup covered by a plastic lid. He stood outside the café for a little more than a minute, then dropped the cup in a rubbish bin and walked along the quay to another flight of steps, this one leading to Warwick Crescent. He paused briefly in the quiet street to light another cigarette and smoked it during the walk to Harrow Road Bridge. His pace now visibly quicker, he continued along Harrow Road, where, at precisely 18:12:32, he stopped suddenly and turned toward the oncoming traffic. A black Mercedes sedan immediately pulled to the curb and the door swung open. Grigori climbed into the rear compartment, and the car lurched forward out of frame. Five seconds later, a man passed through the shot, tapping the tip of his umbrella against the pavement as he moved. Then, from the opposite direction, came a young woman. She wore a car-length leather coat, carried no umbrella, and was hatless in the rain.